Radio signaling system



wsmov L. DE FOREST ET AL RADIO SIGNALING SYSTEM Filed May 23, 1916 Patented Aug. 7, 1928.

LEE DE FOREST AND CHARLES V. LOGWOOD, OF NEW YORK, N. Y., ASSIGNORS TO DE FOREST RADIO TELEPHONE AND TELEGRAPH COMPANY, OF NEW YORK, N. Y., A

CORPORATION OI DELAWARE.

RADIO SIGNALING SYSTEM.

Application filed May 23,

This invention relates to radio signaling systems.

The object of the invention 1s to provide a radio signaling system which is simple and 6 efficient.

A further object of the invention is to provide a method and circuits for producing, radiatin or transmitting and controll ng in accor ance with signals to be sent, h 1gh 1 frequency continuous oscillating electrical waves.

Further objects of the invention W111 appear more fully hereinafter.

The invention consists substantially 1n the circuit arrangements, location and relat1ve arran ement of parts all as will be more fully ereinafter set forth, as shown by the accompanying drawing, and finally polnted out in the appended claims.

Referringto the drawing 2-- Figs. 1, 2 and 3, show various diagrammatic modifications of our invention as applied to radio transmitting systems.

Fig. 4 similarly shows our invention as applied to a receiving system.

Fig. 5 is a detailed modified circuit arrangement employed in connection with the transmitter 26, Fig. 2;

The same part is designated by the same 30 reference numeral wherever it occurs throughout the several views.

In the application of Charles V. Logwood, one of the present applicants, Serial No. 73,641, filed J an. 22, 1916, which has issued 36 as Letters Patent No. 1,218,195, is shown a transmitting system wherein the oscillating circuit associated with the source of oscillating current is at the same time the radiation circuit of the system. Our present application is especially directed to various modifications in such a. system and is also directed to apply the same principles and features to a receiving system, as will be more fully hereinafter explained.

In Fig. 1 we show an oscillion transmitting system wherein' 9 is the oscillion bulb containing the hot or filament electrode 12 and the two cold electrodes 10, 11, preferably a plate and a. grid, respectively, as shown. so Reference numeral 1 designates the antenna which is connected to earth at 5, through the loading inductance 3 and the series condenser 4. The grid electrode 11 is connected to one end of the antenna earth loading coil 3,

1916. Serial N0. 99,283.

through a blocking condenser 6, and is connected to the hot or filament electrode 12 by a high resistance leak path 8.

We have discovered that the efiiciency of such an oscillatin system is greatly increased if an additional connection be made between the filament electrode and the earth, or in other words, to that side of the capacity constituted by the antenna-earth condenser which is furthermost from the plate electrode 10. A convenient method of signaling, therefore, is to insert a telegraphic key 1n this connection, 'as at 20, and a small capacity 7 is preferably inserted in this connection as shown.

The filament electrode 12 is heated by the current source 13, and the plate electrode is connected to the filament through the impedance coil 15 and the. current source 14 in the usual manner, asshown.

We find it preferable to include a condenser 32 in the lead from the plate electrode to the inductance 3.

Fig. 2 embodies essentially the same circuits as Fig. 1, with a. condenser 16, replacing the antenna earth capacity. If the system is to be used for telephony a convenient means for controlling the high frequency by means of the voice is to insert a microphone 26 in the connection between the two series condensers and the hot electrode of the oscillion. We find that it is an advantage to connect the condenser across the microphone 26 as clearer articulation at the receiver is secured thereby.

The same advantage is derived by connecting an inductance 2? across the microphone 26 as shown in Fig. 5.

In Fig. 3, the oscillating circuit connecting the two cold electrodes of the oscillion is also connected at some point, to the hot electrode, preferably at some point 2 on the inductance 3, instead of between the two series condensers 16, 4;, as shown in Fig. 2. In this case one of the condensers is omitted, but the stopping condenser 7 we find to be necessary in the tap lead to the filament of the oscillion to avoid short circuiting the source of B voltage 14:. The condenser 16 may here represent the antenna earth capacity.

Fig. 4 shows the same circuit as in Fig. 1 adapted to a receiving system instead of a generating or transmitting system. In this case a signal indicating device, such as'the receiver 17 is substituted for the impedance coil 15 of the transmitter system, and a battery is preferably used in place of the direct 'current generator, as indicated. The tap lead from the filament to the lower side of the condenser 4, in the oscillating circuit 1, 2, 3, 4, 5, is used to increase the oscillating action of thesystem, and thereby the sensitiveness of the receiver. A choke coil 22, preferably of the spiral pan cake, form is inserted between the telephone receiver 17 and the electrode 10 to prevent any hi l1 frequency oscillation from traversing t e telephone or B circuit 12, 14:, 17 10. A high impedance or leak coil or path 23 is preferably connected across the condenser 4, as shown, to lead off static accumulations from the antenna earth system. It is obvious that this feature may also be applied to the condenser 4 in Fig. 1.

While I we have shown and described specific arrangements embodying our invention, it will be understood that many changes in the details thereof will readily occur to those skilled in the art Without departing from the broad scope of our invention as defined in the claims.

Therefore, what we claim as new and useful and of our own invention, and desire to secure by Letters Patent is-- 1. In an electrical signaling system, an evacuated vessel containing two cold and one hot electrodes, a circuit including an inductance connecting two of said electrodes, a condenser included in a second circuit in series with said inductance, and a connection between one terminal of said condenser and the other of said electrodes, controlling device included in tion.

2. In an electrical signaling system, an evacuated vessel containing two cold and one hot electrodes, an oscillating circuit comprising an inductance and a plurality of said connec- I condensers in series connected across the terminals thereof, connected across two of said electrodes and a separate connection between all of said condensers and the other of said electrodes, and a signal controlling device included in said connection.

3. In an electrical signaling system, an evacuated vessel containing two cold and one hot electrodes, a circuit including an inductance connecting the two cold electrodes, a condenser included in a second circuit in series with said inductance and a connection between one terminal of said condenser and said hot electrode, and a signal controlling device included in, said connection.

4. In an electrical signaling system, an evacuated vessel containing two cold and one hot electrodes, an oscillating circuit comprising an inductance and a plurality of condensers in series connected across the terand a signal minals thereof, connected across said cold electrodes, and a separate connection between all of said condensers and said hot electrode,

and a signal controlling device included in .series connected across the terminals thereof,

connected across said cold electrodes, and a separate connection between both of said condensers and said hot electrode, and a signal controlling device included in said connection.

7. In an electrical signaling system, an evacuated vessel containing two cold and one hot electrodes, a circuit including an inductance connecting two of said electrodes, a connection from said inductance to the other of said electrodes, and a plurality of condensers included in said connection.

8. In an electrical signaling s stem, an evacuated vessel containing two col d and one hot electrodes, an oscillating circuit comprising an inductance and a plurality of condensers in series connected across the terminals thereof, connected across two of said electrodes and a separate connection between all of said condensers and the other of said electrodes and a condenser included in said connection.

9. In an electrical signaling system, an

evacuated vessel containing two cold and one hot electrodes, a circuit including an inductance connecting two cold electrodes, a connection from said inductance to said hot electrode, and a plurality of condensers included in said connection.

10. In an electrical signaling system, an evacuated vessel containing two cold and one hot electrodes, an oscillating circuit comprising an inductance and a plurality of condensers-in series connected across the terminals thereof, connected across said cold electrodes, and a separate connection between all of said condensers and said hot electrode and a. condenser included in said connection.

11. In an electrical signaling system, an evacuated vessel containing two cold and one hot electrodes, an oscillating circuit compris- -ing an inductance and two condensers in iso condensers and the other of said electrodes and a condenser included in said connection.

12. In an electrical signaling system, an evacuated vessel containing two cold and one hot electrodes an oscillating circuit comprising an inductance and two condensers in series connected across the terminals thereof, connected across said, cold electrodes, and a separate connection between both of said condensers and said hot electrode and a condenser included in said connection.

13. In an electrical signaling system, an evacuated vessel containing two cold and one hot electrodes, a circuit including an inductance connecting two of said electrodes and a conductive connection including a condenser extending between said circuit and the other of said electrodes, and a second cir- LEE ma FOREST. CHARLES V. LOGWOOD. 

